Digital adjustable ignition for carbureted Twin Cam models. A total of 16 programmed advance curves in 3 following groups. A) Stock to slightly modified, B) Heavily modified, C) Extreme modified. 8 different RPM. limiter settings from 5750 to 7500 RPM in steps of 250 RPM. This is all adjustable by 2 knobs on the back. Compatible with stock and Dyna coils. All stock ignition sensors are used. The unit will mount in the same place, and use the same connectors as the stock black box it replaces.